Weird mount problem

[Bob Nielsen]

I added a second hard drive which already has a vfat and two ext3 
partitions.  When I try to mount one of these, I get an error message:

mount: /dev/hdb2 already mounted or /mnt busy

The device is not mounted and there is nothing else mounted to /mnt.  Is 
there something else which would cause this error message?  Fdisk 
recognizes the disk and correctly displays its partitions.

Bob